/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package javax.servlet.http;

import java.io.Serializable;
import java.text.MessageFormat;
import java.util.Locale;
import java.util.ResourceBundle;

/**
 * Creates a cookie, a small amount of information sent by a servlet to a Web
 * browser, saved by the browser, and later sent back to the server. A cookie's
 * value can uniquely identify a client, so cookies are commonly used for
 * session management.
 * <p>
 * A cookie has a name, a single value, and optional attributes such as a
 * comment, path and domain qualifiers, a maximum age, and a version number.
 * Some Web browsers have bugs in how they handle the optional attributes, so
 * use them sparingly to improve the interoperability of your servlets.
 * <p>
 * The servlet sends cookies to the browser by using the
 * {@link HttpServletResponse#addCookie} method, which adds fields to HTTP
 * response headers to send cookies to the browser, one at a time. The browser
 * is expected to support 20 cookies for each Web server, 300 cookies total, and
 * may limit cookie size to 4 KB each.
 * <p>
 * The browser returns cookies to the servlet by adding fields to HTTP request
 * headers. Cookies can be retrieved from a request by using the
 * {@link HttpServletRequest#getCookies} method. Several cookies might have the
 * same name but different path attributes.
 * <p>
 * Cookies affect the caching of the Web pages that use them. HTTP 1.0 does not
 * cache pages that use cookies created with this class. This class does not
 * support the cache control defined with HTTP 1.1.
 * <p>
 * This class supports both the Version 0 (by Netscape) and Version 1 (by RFC
 * 2109) cookie specifications. By default, cookies are created using Version 0
 * to ensure the best interoperability.
 */
public class Cookie implements Cloneable, Serializable {

	private static final long serialVersionUID = 1L;

	private static final String LSTRING_FILE = "javax.servlet.http.LocalStrings";
	private static final String tspecials = ",; ";

	//
	// The value of the cookie itself.
	//
	private static final String tspecials2NoSlash = "()<>@,;:\\\"[]?={} \t";
	private static final String tspecials2WithSlash = tspecials2NoSlash + "/";

	//
	// Attributes encoded in the header's cookie fields.
	//
	private static final String tspecials2;
	/**
	 * If set to true, we parse cookies strictly according to the servlet,
	 * cookie and HTTP specs by default.
	 */
	private static final boolean STRICT_SERVLET_COMPLIANCE;
	/**
	 * If set to true, the <code>/</code> character will be treated as a
	 * separator. Default is usually false. If STRICT_SERVLET_COMPLIANCE==true
	 * then default is true. Explicitly setting always takes priority.
	 */
	private static final boolean FWD_SLASH_IS_SEPARATOR;
	/**
	 * If set to true, enforce the cookie naming rules in the spec that require
	 * no separators in the cookie name. Default is usually false. If
	 * STRICT_SERVLET_COMPLIANCE==true then default is true. Explicitly setting
	 * always takes priority.
	 */
	private static final boolean STRICT_NAMING;
	private static ResourceBundle lStrings = ResourceBundle.getBundle(LSTRING_FILE);

	static {
		STRICT_SERVLET_COMPLIANCE = Boolean.parseBoolean(
				System.getProperty(
						"org.apache.catalina.STRICT_SERVLET_COMPLIANCE",
						"false"));

		String fwdSlashIsSeparator = System.getProperty(
				"org.apache.tomcat.util.http.ServerCookie.FWD_SLASH_IS_SEPARATOR");
		if (fwdSlashIsSeparator == null) {
			FWD_SLASH_IS_SEPARATOR = STRICT_SERVLET_COMPLIANCE;
		} else {
			FWD_SLASH_IS_SEPARATOR = Boolean.parseBoolean(fwdSlashIsSeparator);
		}

		if (FWD_SLASH_IS_SEPARATOR) {
			tspecials2 = tspecials2WithSlash;
		} else {
			tspecials2 = tspecials2NoSlash;
		}

		String strictNaming = System.getProperty(
				"org.apache.tomcat.util.http.ServerCookie.STRICT_NAMING");
		if (strictNaming == null) {
			STRICT_NAMING = STRICT_SERVLET_COMPLIANCE;
		} else {
			STRICT_NAMING = Boolean.parseBoolean(strictNaming);
		}

	}

	private String name; // NAME= ... "$Name" style is reserved
	private String value; // value of NAME
	private String comment; // ;Comment=VALUE ... describes cookie's use
	// ;Discard ... implied by maxAge < 0
	private String domain; // ;Domain=VALUE ... domain that sees cookie
	private int maxAge = -1; // ;Max-Age=VALUE ... cookies auto-expire
	private String path; // ;Path=VALUE ... URLs that see the cookie
	private boolean secure; // ;Secure ... e.g. use SSL
	private int version = 0; // ;Version=1 ... means RFC 2109++ style
	private boolean httpOnly; // Not in cookie specs, but supported by browsers

	/**
	 * Constructs a cookie with a specified name and value.
	 * <p>
	 * The name must conform to RFC 2109. That means it can contain only ASCII
	 * alphanumeric characters and cannot contain commas, semicolons, or white
	 * space or begin with a $ character. The cookie's name cannot be changed
	 * after creation.
	 * <p>
	 * The value can be anything the server chooses to send. Its value is
	 * probably of interest only to the server. The cookie's value can be
	 * changed after creation with the <code>setValue</code> method.
	 * <p>
	 * By default, cookies are created according to the Netscape cookie
	 * specification. The version can be changed with the
	 * <code>setVersion</code> method.
	 *
	 * @param name  a <code>String</code> specifying the name of the cookie
	 * @param value a <code>String</code> specifying the value of the cookie
	 * @throws IllegalArgumentException if the cookie name contains illegal characters (for example,
	 *                                  a comma, space, or semicolon) or it is one of the tokens
	 *                                  reserved for use by the cookie protocol
	 * @see #setValue
	 * @see #setVersion
	 */
	public Cookie(String name, String value) {
		if (name == null || name.length() == 0) {
			throw new IllegalArgumentException(
					lStrings.getString("err.cookie_name_blank"));
		}
		if (!isToken(name) ||
				name.equalsIgnoreCase("Comment") // rfc2019
				||
				name.equalsIgnoreCase("Discard") // 2019++
				||
				name.equalsIgnoreCase("Domain") ||
				name.equalsIgnoreCase("Expires") // (old cookies)
				||
				name.equalsIgnoreCase("Max-Age") // rfc2019
				|| name.equalsIgnoreCase("Path") ||
				name.equalsIgnoreCase("Secure") ||
				name.equalsIgnoreCase("Version") || name.startsWith("$")) {
			String errMsg = lStrings.getString("err.cookie_name_is_token");
			Object[] errArgs = new Object[1];
			errArgs[0] = name;
			errMsg = MessageFormat.format(errMsg, errArgs);
			throw new IllegalArgumentException(errMsg);
		}

		this.name = name;
		this.value = value;
	}

	/**
	 * Returns the comment describing the purpose of this cookie, or
	 * <code>null</code> if the cookie has no comment.
	 *
	 * @return a <code>String</code> containing the comment, or
	 * <code>null</code> if none
	 * @see #setComment
	 */
	public String getComment() {
		return comment;
	}

	/**
	 * Specifies a comment that describes a cookie's purpose. The comment is
	 * useful if the browser presents the cookie to the user. Comments are not
	 * supported by Netscape Version 0 cookies.
	 *
	 * @param purpose a <code>String</code> specifying the comment to display to the
	 *                user
	 * @see #getComment
	 */
	public void setComment(String purpose) {
		comment = purpose;
	}

	/**
	 * Returns the domain name set for this cookie. The form of the domain name
	 * is set by RFC 2109.
	 *
	 * @return a <code>String</code> containing the domain name
	 * @see #setDomain
	 */
	public String getDomain() {
		return domain;
	}

	/**
	 * Specifies the domain within which this cookie should be presented.
	 * <p>
	 * The form of the domain name is specified by RFC 2109. A domain name
	 * begins with a dot (<code>.foo.com</code>) and means that the cookie is
	 * visible to servers in a specified Domain Name System (DNS) zone (for
	 * example, <code>www.foo.com</code>, but not <code>a.b.foo.com</code>). By
	 * default, cookies are only returned to the server that sent them.
	 *
	 * @param pattern a <code>String</code> containing the domain name within which
	 *                this cookie is visible; form is according to RFC 2109
	 * @see #getDomain
	 */
	public void setDomain(String pattern) {
		domain = pattern.toLowerCase(Locale.ENGLISH); // IE allegedly needs this
	}

	/**
	 * Returns the maximum age of the cookie, specified in seconds, By default,
	 * <code>-1</code> indicating the cookie will persist until browser
	 * shutdown.
	 *
	 * @return an integer specifying the maximum age of the cookie in seconds; if
	 * negative, means the cookie persists until browser shutdown
	 * @see #setMaxAge
	 */
	public int getMaxAge() {
		return maxAge;
	}

	/**
	 * Sets the maximum age of the cookie in seconds.
	 * <p>
	 * A positive value indicates that the cookie will expire after that many
	 * seconds have passed. Note that the value is the <i>maximum</i> age when
	 * the cookie will expire, not the cookie's current age.
	 * <p>
	 * A negative value means that the cookie is not stored persistently and
	 * will be deleted when the Web browser exits. A zero value causes the
	 * cookie to be deleted.
	 *
	 * @param expiry an integer specifying the maximum age of the cookie in
	 *               seconds; if negative, means the cookie is not stored; if zero,
	 *               deletes the cookie
	 * @see #getMaxAge
	 */
	public void setMaxAge(int expiry) {
		maxAge = expiry;
	}

	/**
	 * Returns the path on the server to which the browser returns this cookie.
	 * The cookie is visible to all subpaths on the server.
	 *
	 * @return a <code>String</code> specifying a path that contains a servlet
	 * name, for example, <i>/catalog</i>
	 * @see #setPath
	 */
	public String getPath() {
		return path;
	}

	// Note -- disabled for now to allow full Netscape compatibility
	// from RFC 2068, token special case characters
	//
	// private static final String tspecials = "()<>@,;:\\\"/[]?={} \t";

	/**
	 * Specifies a path for the cookie to which the client should return the
	 * cookie.
	 * <p>
	 * The cookie is visible to all the pages in the directory you specify, and
	 * all the pages in that directory's subdirectories. A cookie's path must
	 * include the servlet that set the cookie, for example, <i>/catalog</i>,
	 * which makes the cookie visible to all directories on the server under
	 * <i>/catalog</i>.
	 * <p>
	 * Consult RFC 2109 (available on the Internet) for more information on
	 * setting path names for cookies.
	 *
	 * @param uri a <code>String</code> specifying a path
	 * @see #getPath
	 */
	public void setPath(String uri) {
		path = uri;
	}

	/**
	 * Returns <code>true</code> if the browser is sending cookies only over a
	 * secure protocol, or <code>false</code> if the browser can send cookies
	 * using any protocol.
	 *
	 * @return <code>true</code> if the browser uses a secure protocol;
	 * otherwise, <code>true</code>
	 * @see #setSecure
	 */
	public boolean getSecure() {
		return secure;
	}

	/**
	 * Indicates to the browser whether the cookie should only be sent using a
	 * secure protocol, such as HTTPS or SSL.
	 * <p>
	 * The default value is <code>false</code>.
	 *
	 * @param flag if <code>true</code>, sends the cookie from the browser to the
	 *             server only when using a secure protocol; if
	 *             <code>false</code>, sent on any protocol
	 * @see #getSecure
	 */
	public void setSecure(boolean flag) {
		secure = flag;
	}

	/**
	 * Returns the name of the cookie. The name cannot be changed after
	 * creation.
	 *
	 * @return a <code>String</code> specifying the cookie's name
	 */
	public String getName() {
		return name;
	}

	/**
	 * Returns the value of the cookie.
	 *
	 * @return a <code>String</code> containing the cookie's present value
	 * @see #setValue
	 * @see Cookie
	 */
	public String getValue() {
		return value;
	}

	/**
	 * Assigns a new value to a cookie after the cookie is created. If you use a
	 * binary value, you may want to use BASE64 encoding.
	 * <p>
	 * With Version 0 cookies, values should not contain white space, brackets,
	 * parentheses, equals signs, commas, double quotes, slashes, question
	 * marks, at signs, colons, and semicolons. Empty values may not behave the
	 * same way on all browsers.
	 *
	 * @param newValue a <code>String</code> specifying the new value
	 * @see #getValue
	 * @see Cookie
	 */
	public void setValue(String newValue) {
		value = newValue;
	}

	/**
	 * Returns the version of the protocol this cookie complies with. Version 1
	 * complies with RFC 2109, and version 0 complies with the original cookie
	 * specification drafted by Netscape. Cookies provided by a browser use and
	 * identify the browser's cookie version.
	 *
	 * @return 0 if the cookie complies with the original Netscape specification;
	 * 1 if the cookie complies with RFC 2109
	 * @see #setVersion
	 */
	public int getVersion() {
		return version;
	}

	/**
	 * Sets the version of the cookie protocol this cookie complies with.
	 * Version 0 complies with the original Netscape cookie specification.
	 * Version 1 complies with RFC 2109.
	 * <p>
	 * Since RFC 2109 is still somewhat new, consider version 1 as experimental;
	 * do not use it yet on production sites.
	 *
	 * @param v 0 if the cookie should comply with the original Netscape
	 *          specification; 1 if the cookie should comply with RFC 2109
	 * @see #getVersion
	 */
	public void setVersion(int v) {
		version = v;
	}

	/**
	 * Tests a string and returns true if the string counts as a reserved token
	 * in the Java language.
	 *
	 * @param possibleToken the <code>String</code> to be tested
	 * @return <code>true</code> if the <code>String</code> is a reserved token;
	 * <code>false</code> if it is not
	 */
	private boolean isToken(String possibleToken) {
		int len = possibleToken.length();

		for (int i = 0; i < len; i++) {
			char c = possibleToken.charAt(i);

			if (c < 0x20 || c >= 0x7f || tspecials.indexOf(c) != -1 ||
					(STRICT_NAMING && tspecials2.indexOf(c) != -1)) {
				return false;
			}
		}
		return true;
	}

	/**
	 * Overrides the standard <code>java.lang.Object.clone</code> method to
	 * return a copy of this cookie.
	 */
	@Override
	public Object clone() {
		try {
			return super.clone();
		} catch (CloneNotSupportedException e) {
			throw new RuntimeException(e.getMessage());
		}
	}

	/**
	 * Gets the flag that controls if this cookie will be hidden from scripts on
	 * the client side.
	 *
	 * @return <code>true</code> if the cookie is hidden from scripts, else
	 * <code>false</code>
	 * @since Servlet 3.0
	 */
	public boolean isHttpOnly() {
		return httpOnly;
	}

	/**
	 * Sets the flag that controls if this cookie will be hidden from scripts on
	 * the client side.
	 *
	 * @param httpOnly The new value of the flag
	 * @since Servlet 3.0
	 */
	public void setHttpOnly(boolean httpOnly) {
		this.httpOnly = httpOnly;
	}
}
